Abstract:This experiment extracted collagen from the by-products of anglerfish （Lophius litulon），and analyzed its physicochemical properties through ultraviolet （UV） spectroscopy，Fourier transform infrared spectroscopy （FT-IR），and polyacrylamide gel electrophoresis. The optimal process for collagen enzymatic hydrolysis was determined through single-factor and orthogonal experiments to obtain L. litulon bone collagen peptide（LBCP），and the in vitro DPPH free radical，ABTS+ free radical，and superoxide anion free radical scavenging capacities were measured to preliminarily evaluate its in vitro antioxidant capacity. The results showed that the maximum UV absorption of L. litulon bone collagen was at 233 nm，and there were five characteristic absorption peaks corresponding to amide A，B，I，II，and III in the infrared spectrum.Sodium dodecyl sulfate polyacrylamide gel electrophoresis（SDS-PAGE）analysis showed the presence of two α1 and one α2 peptide chains，confirming its compliance with the characteristics of type I collagen. The optimal enzymatic hydrolysis process for L. litulon bone collagen peptide was identified as follows:extraction temperature of 30 ℃，enzyme dosage of 5%，enzymatic hydrolysis time of 2 h，and solid-liquid ratio of 20∶1 （mg/mL）. The L. litulon bone collagen peptide obtained through this process demonstrated good antioxidant activity. The results showed that median inhibition concentrations （IC??） for DPPH free radicals，ABTS+ free radicals，and superoxide anion free radical scavenging rates were 14.74，1.284，and 3.163 mg/mL，respectively. Compared to the pre-hydrolysis state，the antioxidant activities were significantly improved.